Hey Gang,
Had a friend ask if could cast a small item in stainless steel.
I know stainless can be cast, but is it so hi tech that you need
a mega buck foundry? Can any one suggest any books, articles,
videos or provide any advice?
TIA (thanks in advance) for ay help!
Dave
Had a friend ask if could cast a small item in stainless steel.
I know stainless can be cast, but is it so hi tech that you need
a mega buck foundry? Can any one suggest any books, articles,
videos or provide any advice?
Hi Dave,
Some years ago, I talked to a dentist, they used a
chrome-cobalt-alloy which they refered to as stainless.
Actually, it has very little iron in it. He cast it using an
acetylene/oxigene torch and a spring driven casting machine.
Once he cast an orchid blossom directly from the plant as a
model, and it came out in every detail. The metal, however, is
really hard, I coudn’t drill it with a tool steel drill. So
perhaps ask your dentist, Markus
Dave and Marcus,
I learned to cast particial dentures when I was in Dental Lab
school. As Marcus stated a chrome cobalt alloy is used. Aside
from a greater heat required to melt the alloy, a special
investment is used to make the mold. Maybe Skip is more up to
date on this than I am. If you call a local dental lab,
especially one specializing in dentures, they can probably be of
more help than your dentist. Remember, the stuff is very hard,
its like grinding on an old bumper.
Something else just struck me. At the time I was getting out of
the dental lab business we were starting to use non-precious
metals for crowns. Luckily, the lab I worked in refused to get
into them. It was an issue of nickel content and the hardness
of the metal as compared to tooth enamel. Anyway, I’m sure Skip
knows something about how this movement resolved itself and if
the non-precious is still used and how its done.
Richard
Partial Dentures are made from chrome-cobalt metal, the very
same metal used for screws, plates, etc. that are implanted into
the body either temporarily, or permanently. This metal requires
a very high heat investment that is not required to reproduce
extra-fine detail like crown and bridge investment. It is stable
and does reproduce your original pretty closely. This
metal/proceedure is best left to specialists. If you need
something done in this metal, take your wax-up to a dental lab
that specializes in chrome casting and ask them to do it. I’m
sure they will do it for you for a nominal fee. The tech will
probably ride it along with another casting if it isn’t very big.
Be prepared to grind your ass off, and burn your fingers a lot.
This crap is harder than Janet Renos testicles! The techs that
finish this metal keep a bowl of water handy, otherwise they
would be there all day working on one object. If the Egyptians
of antiquity had this metal, the objects would look like they
were made yesterday even after being buried for 4000 years.
Now to nickel chrome. This metal requires a high heat dental
alloy investment capable of a 1500-1700 degree F. burnout. Its
specific gravity is fairly light compared to precious metals, so
it requires an extra wind on the centrifugal casting machine and
the attendant re-balancing of the broken-arm. The metal is cheep
enough though and you should be able to find it at any dental
supply house. There are many brands out there, but for your use
you needn’t worry about which brand to buy. Ask the supply house
for a tech sheet and follow their instructions to the letter.
If you are going to solder this to anything, as always you must
be clean, but also, once you put the flame on it you don’t ever
take it off until you are complete, or the metal will oxidize in
a flash and you will need to start from scratch on the soldering.
Before you reuse the button for a new casting you must sand
blast or grind it clean of all oxides. If you don’t add at least
50% new metal to the next casting you will get pitting that will
make anything you have ever gotten in precious metal seem
inconsequential by comparison.
When you finish this metal, don’t even try steel burrs, you need
carbide(good quality) and aluminous oxide stones. Rubber it
with a harder grit rubber wheel or point and work your way to
softer grit. You can then use a mounted brush with a carborundum
based compound(tripoli may work) then red rouge. It will take a
super shine.
It is hard to cast, hard to finish, and about 18% of the people
are nickel sensitive to a greater or lesser degree. I first used
this metal 20 yrs. ago when I managed a friends lab and started
noticing that I got nose bleeds, and the unavoidable cuts, nicks,
and scrapes would not heal plus the area under my wedding ring
was raw, so before I went on a 2 week vacation I cast a thin
10x10mm square of this metal. At the beginning of the second
week of the fishing trip, I put it on the pad of a band-aid and
kept it taped to the inside of my upper arm. Within 4 days I had
a red raw welt. I will not have this metal in my mouth or in my
lab.
If I can help in any way, E-mail me directly.
Regards,
Skip
Skip Meister
NRA Endowment and
Instructor
@Skip_Meister
05/19/9721:50:00Investment to cast stainless steel is made by ransom & randolph.
It is called Astro-vest and is available in 50 lb. Pails from
most r&r distributors.
To:
W Clark
Markus Ellermeier
Richard Knight
Skip Meister
Thanks for all the info on stainless steel casting. I’ve gotten
several good ideas from the posts!
Dave
Now to nickel chrome. and about 18% of the people are nickel
sensitive to a greater or lesser degree. I will not have this
metal in my mouth or in my lab.
Hi Skip, In Germany, nickel isn’t allowed any more as part of
alloys touching skin (that is you are not allowed to use alloys
that give off a certain amount of nickel in a given period of
time - you know bureaucrats), so they make white gold now with
cobalt (better?), which is nearly like palladium alloyed white
gold. Also, dentists mustn’t use solders with cadmium, and
refiners sell cadmium free solders increasingly to the
jewellers, too. Markus